I 



CONTRIBUTIONS TO GEOLOGY 



THE subject of the structure of the earth's 

 crust appears to have engaged Michell's 

 attention long before he left Cambridge, 

 though in this as in other investigations, 

 he was in no hurry to publish his obser- 

 vations. He was ultimately led to embody 

 the results of his studies in this subject 

 in the paper on Earthquakes which he 

 communicated to the Royal Society in 

 the spring of the year I76O 1 . This re- 

 markable Essay is not only a dissertation on 

 earthquakes, but contains an exposition 

 of the structure of the terrestrial crust 



1 The full title of this paper was as follows : 

 "Conjectures concerning the Cause, and Observa- 

 tions upon the Phaenomena of Earthquakes ; particu- 

 larly of that great Earthquake of the first of November 

 1755 which proved so fatal to the City of Lisbon, 

 and whose Effects were felt as far as Africa, and more 

 or less throughout almost all Europe ; By the 

 Reverend John Michell M.A. Fellow of Queens' 

 College, Cambridge." It appeared in vol. 51 (1760) 

 of the Philosophical Transactions^ pp. 566-634. 



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